This invention relates in general to drain and overflow systems for bathtubs and is directed more particularly to an improved linkage adjustment means and to a simplified method of installation.
The most widely used mechanism for controlling the drainage from a bathtub is a device known as a trip lever bath waste and overflow. Included in this product is a drain tube which leads from the tub drain and connects to a tee fitting. A vertical overflow tube extends downwardly from the elevated overflow port of the tub and connects to the upper end of the tee. A hollow cylinder known as a drop cylinder serves as a valve to control drainage from the tub and is located within the vertical portion of the tee. An adjustable linkage, usually consisting of two connected brass rods and a brass clevis connects the drop cylinder to a trip lever mechanism located at the tub overflow port. Moving the trip lever arm up or down closes or opens the tee to tub drainage.
Since the vertical distance from the overflow port to the drain port varies considerably among the various styles and brands of tubs, the overflow tube fits into the tee in a telescoping manner so that it can be raised or lowered as needed for proper installation. This requires that the linkage length also be adjustable. If the linkage is too short, the drop cylinder cannot seat inside the tee and close off the tube drainage. If the linkage is too long, the drop cylinder cannot clear the port inside the tee through which the tub drainage passes and may reduce the drainage rate.
Adjusting the linkage length normally is accomplished by threading the upper brass rod through an internally threaded hole in the bottom of the clevis. Threading the brass rod up or down through the hole in the clevis changes the overall linkage length as needed. A brass nut is then tightened securely against the bottom of the clevis to keep the length from changing.
It is important to recognize that there is no universally accepted method of determining proper linkage length. Some manufacturers of bath wastes simply leave it to the plumber to figure out the proper length. Those manufacturers that do include linkge adjustment instructions with each bath waste tend to have their own method depending upon their particular design. Probably the most common method is to rest the drop cylinder on the bottom of the tub and then visually align some portion of the upper linkage with some portion of the overflow port of perhaps the retainer plate which holds the overflow ell securely to the overflow port. This procedure is subject to several possible errors.
First, with the drop cylinder resting on the tub bottom, the linkage length can be altered at least 3/16" due to the flexible connection between the two brass rods. Second, many tubs are not level at the drain port, and this can lead to inaccuracy. Third, holding the linkage assembly upright so that it is fully extended, yet making sure that the drop cylinder remains in contact with the tub bottom is a difficult procedure which is subject to error. Fourth, visual horizontal alignment of two parts below the top edge of the tub is not always accurate. Fifth, some plumbers rely on memory as to the various alignment methods used.
If the linkage length is not correct, the linkage assembly must be removed, the length must be changed, the linkage must be reinstalled and it must then be retested. If adequate testing is not accomplished when the tub is installed, the plunger may have to make a special trip to adjust the linkage. For an increasing number of plumbing contractors, the labor costs associated with readjusting the linkage length on trip lever bath wastes have become so great that they are now using a more expensive bath waste that does not contain a linkage of any kind.
It is thus apparent that a need exists for a method of quickly and accurately adjusting the overall linkage length in a trip lever bath waste in a manner that is quick, accurate, and easy to understand and remember. The primary goal of the present invention is to meet that need.
More specifically, it is an object of the invention to provide, in a trip lever bath waste and overflow assembly, a linkage adjustment system and a method that avoids reliance on visual alignment. The human error that inevitably results from attempts at visual alignment is thus elminated.
Another object of the invention is to provide a linkage adjustment system and method in which adjustment of the linkage can be carried out quickly and with a minimal difficulty.
A further object of the invention is to provide a linkage adjustment system and method wherein the procedure to be followed is easily understood and remembered.
An additional object of the invention is to provide a linkage adjustment system and method that are well adapted to be used with a wide variety of of linkage designs.
Other and further objects of the invention, together with the features of novelty appurtenant thereto, will appear in the course of the following description.